Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The severe combined immunodeficient (SCID) mouse model of human immunodeficiency virus (HIV) encephalitis exhibits many of the histopathological and pathophysiological features of human HIV-associated dementia (HAD). Although deficits that may resemble HAD in humans have been reported for HIV-infected SCID mice, the cognitive deficit aspect of the model has very limited empirical support. Here, the authors report that HIV-infected SCID mice display cognitive deficits on a task requiring the animal to learn and remember the spatial relationship of cues in its environment in order to locate a submerged platform in a Morris water maze. The cognitive deficits manifest as longer latencies to locate the platform on the last day of the maze acquisition period and during a retention test 8 days later. Control experiments indicated that the poor performance by HIV-infected mice in comparison to controls was not due to impaired motor function or swimming ability, impaired visual acuity, or increased susceptibility to fatigue. Thus, the increased times required for HIV-infected mice to locate the submerged platform during the acquisition and memory tests likely reflect a cognitive deficit, rather than sensorimotor or emotional abnormalities. These behavioral deficits are associated with significant increases in astrogliosis and microgliosis in the HIV-infected mice. The results of this study strengthen the SCID mouse model of HIV encephalitis by definitively establishing cognitive deficits for the model in addition to its previously reported neuropathological features.
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PMID:The severe combined immunodeficient (SCID) mouse model of human immunodeficiency virus encephalitis: deficits in cognitive function. 1520 29

Chemokines and cytokines play a critical role in HIV infection, serving both to modulate virus replication and to recruit target cells to the site of infection. Platelet-derived growth factor (PDGF), a mitogen and chemoattractant for a wide variety of cells, is secreted by macrophages. Since macrophages are the target cells for lentiviral infection in the brain and PDGF is a known inducer of macrophage chemoattractant protein-1 (MCP)-1, a potent chemokine closely associated with HIV encephalitis, we investigated the association of PDGF-B chain (PDGF-B) with encephalitis in macaques caused by simian human immunodeficiency virus (SHIV), a chimera of HIV and SIV. Northern blot analysis confirmed elevated expression of PDGF-B chain mRNA in the brains from encephalitic macaques. Validation of these in vivo studies was confirmed in rhesus macrophage cultures infected with SHIV(KU2) in which we demonstrated heightened expression of PDGF-B chain mRNA. Nuclear run-off analysis established transcriptional up-regulation of PDGF-B chain in virus-inoculated macrophage cultures. Reciprocally, addition of exogenous PDGF enhanced virus replication and MCP-1 expression in these cells. Inhibition of virus replication by tyrosine kinase inhibitor, STI-571, and by PDGF-B antisense oligonucleotides confirmed the specificity of the PDGF effect. Relevance of these findings was confirmed by analysis of archival brain tissue from SHIV encephalitic and non-encephalitic macaques for PDGF-B chain expression. PDGF-B chain protein expression was observed in the virus-infected cells in microglial nodules in the brains of SHIV-encephalitic macaques.
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PMID:Association of platelet-derived growth factor-B chain with simian human immunodeficiency virus encephalitis. 1533 6

Recent evidence suggests that injection drug users who abuse heroin are at increased risk of CNS complications from human immunodeficiency virus (HIV) infection. Opiate drugs may intrinsically alter the pathogenesis of HIV by directly modulating immune function and by directly modifying the CNS response to HIV. Despite this, the mechanisms by which opiates increase the neuropathogenesis of HIV are uncertain. In the present study, we describe the effect of morphine and the HIV-1 protein toxin Tat(1-72) on astroglial function in cultures derived from ICR mice. Astroglia maintain the blood-brain barrier and influence inflammatory signaling in the CNS. Astrocytes can express mu-opioid receptors, and are likely targets for abused opiates, which preferentially activate mu-opioid receptors. While Tat alone disrupts astrocyte function, when combined with morphine, Tat causes synergistic increases in [Ca(2+)](i). Moreover, astrocyte cultures treated with morphine and Tat showed exaggerated increases in chemokine release, including monocyte chemoattractant protein-1 (MCP-1) and regulated on activation, normal T cell expressed and secreted (RANTES), as well as interleukin-6 (IL-6). Morphine-Tat interactions were prevented by the mu-opioid receptor antagonist beta-funaltrexamine, or by immunoneutralizing Tat(1-72) or substituting a nontoxic, deletion mutant (Tat(Delta31-61)). Our findings suggest that opiates may increase the vulnerability of the CNS to viral entry (via recruitment of monocytes/macrophages) and ensuing HIV encephalitis by synergistically increasing MCP-1 and RANTES release by astrocytes. The results further suggest that astrocytes are key intermediaries in opiate-HIV interactions and disruptions in astroglial function and inflammatory signaling may contribute to an accelerated neuropathogenesis in HIV-infected individuals who abuse opiates.
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PMID:Synergistic increases in intracellular Ca2+, and the release of MCP-1, RANTES, and IL-6 by astrocytes treated with opiates and HIV-1 Tat. 1563 Jul 4

Complications from human immunodeficiency virus (HIV)/acquired immune deficiency syndrome are notorious for mimicking other neurological diseases. We describe a case of HIV encephalitis presenting with the classic clinical features of Huntington's Disease in a woman without known HIV risk factors or other clinical stigmata suggestive of immunosuppression. This case reminds us that HIV should be part of the differential diagnosis in unexplainable neurological diseases.
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PMID:HIV encephalitis simulating Huntington's disease. 1570 6

The use of methamphetamine (METH) continues to increase the risk of human immunodeficiency virus (HIV) transmission within both homosexual and heterosexual drug abuser groups. Neurological studies indicate that the progression of HIV encephalitis is also enhanced by illicit drug use. Recently, the authors' studies in the postmortem brains of HIV-positive METH users have shown that the combined effects of HIV and METH selectively damage calbindin (CB)-immunoreactive nonpyramidal neurons, which may contribute to the behavioral alterations observed in these patients. To better understand the mechanisms of toxicity associated with exposure to HIV and METH, neuronal survival, phenotypic markers, levels of oxidative stress, and mitochondrial potential were assessed in vitro in the hippocampal neuronal cell line, HT22, and in primary human neurons exposed to the HIV Tat protein and/or METH. Both Tat and METH were toxic to neurons in a time- and dose-dependent fashion. Neurons exposed to a combination of Tat and METH displayed early evidence of neuronal damage at 6 h, characterized by a decrease in CB and microtubule-associated protein 2 (MAP2) immunoreactivity followed by more extensive cell death at 24 h. Loss of CB immunoreactivity associated with the combined exposure to Tat and METH was accompanied by mitochondrial damage with increased levels of oxidative stress. The toxic effects of Tat and METH were inhibited by blocking mitochondrial uptake of intracellular calcium, whereas blocking calcium flux in the endoplasmic reticulum or from the extracellular environment had no effect on Tat and METH toxicity. These studies indicate that in vitro, when combined, the HIV protein Tat and METH damage CB-immunoreactive nonpyramidal neurons by dysregulating the mitochondrial calcium potential. In combination, Tat and METH may increase cell injury and death, thereby enhancing brain metabolic disturbances observed in HIV-positive METH users in clinical populations.
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PMID:The role of mitochondrial alterations in the combined toxic effects of human immunodeficiency virus Tat protein and methamphetamine on calbindin positive-neurons. 1576 4

We experienced 8 cases of progressive multifocal leukoencephalopathy (PML) complicated by human immunodeficiency virus (HIV) type-1 infection from 1985 to 1999. These cases showed dementia, bradykinesia, dysarthria, hemiparesis, and so on. All of the cases were severely immunocompromised hosts, because none had more than 150/mm3 CD4 + lymphocytes; indeed, 5 of the cases were below 20/mm3. Other neurological complications except PML were primary CNS lymphoma, HIV encephalitis, and CMV encephalitis. The mean life durations was 7.6 months after the first symptom appeared, for all but one of the patients; the exceptional patient lived for 24 months after. Autopsy studies of the central nervous systems were performed for 7 cases, all of which showed extensive demyelinating lesions of the white matter, and in some cases these extended into the spinal cord. In contrast to Western countries, in Japan there have been few reports of AIDS-associated PML. Thus, this report was thought to be important here.
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PMID:[Clinical investigation of the 8 cases with AIDS (acquired immunodeficiency syndrome)-associated progressive multifocal leukoencephalopathy (PML)]. 1578 5

The objective of this study was to examine the neuropathological changes in the brain of patients infected with human immunodeficiency virus (HIV) in the Tanzanian capital Dar Es Salaam, and investigate whether the prevalence of different forms of HIV-related neuropathology varies from other countries. The subjects were patients with risk factors for HIV infection in whom forensic autopsies were performed between 1997 and 1999. In Dar Es Salaam, forensic autopsy constitutes more than 90% of all autopsies, because hospital autopsy is limited due to socio-cultural and religious reasons. HIV infection was identified in 52 of 143 patients selected from forensic autopsies. Neuropathological findings were observed in 31 of 52 HIV-infected patients; these include lymphocytic meningitis 19, bacterial meningitis 3, tuberculous brain abscess 3, cryptococcal meningitis 3, basal ganglia calcification 3, and toxoplasma encephalitis 1. HIV encephalitis, lymphoma, and cytomegalovirus encephalitis could not be found in this study. Whereas the findings should be interpreted cautiously because of possible autopsy bias and a low percentage of cases examined compared to the total number of HIV-infected patients in Tanzania, our observations provide information on the likely diagnostic possibilities to be considered in the evaluation and management of HIV-infected patients with neurological symptoms in Tanzania. In the face of decreased hospital autopsy, most studies have focused mainly on the end-stage HIV disease; forensic autopsy is a potential source of materials for studies on HIV disease spectrum at different stages.
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PMID:Neuropathology of human immunodeficiency virus infection: a forensic autopsy study in Dar Es Salaam, Tanzania. 1593 44

Mononuclear phagocytes (MP: monocytes, dendritic cells, and tissue macrophages) are host cells for the human immunodeficiency viruses types 1 and 2. MPs are both the first lines of defense and vehicles for viral dissemination in the infected human host. Viral infection of MP can affect the disease directly during interstitial pneumonitis and HIV encephalitis. Both revolve around MP secretions of immune regulatory and neurotoxic factors. Clearly, laboratory models that mimic disease need to include primary human MP infected with viral isolates obtained from diseased tissues. Over the past two decades our laboratory has developed state-of-the-art methods for isolation and propagation of monocytes from peripheral blood. This technology directly supports work at the University of Nebraska Medical Center as well as research performed throughout the United States, including the laboratories of Drs. Mario Stevenson, William Tyor, David Volsky, Loyda Melendez, and Mary-Jane Potash, among others. The importance of these cells as targets for virus and reservoirs of persistent infection are discussed.
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PMID:Isolation, propagation, and HIV-1 infection of monocyte-derived macrophages and recovery of virus from brain and cerebrospinal fluid. 1606 65

Opiate drug abuse, through selective actions at mu-opioid receptors (MOR), exacerbates the pathogenesis of human immunodeficiency virus-1 (HIV-1) in the CNS by disrupting glial homeostasis, increasing inflammation, and decreasing the threshold for pro-apoptotic events in neurons. Neurons are affected directly and indirectly by opiate-HIV interactions. Although most opiates drugs have some affinity for kappa (KOR) and/or delta (DOR) opioid receptors, their neurotoxic effects are largely mediated through MOR. Besides direct actions on the neurons themselves, opiates directly affect MOR-expressing astrocytes and microglia. Because of their broad-reaching actions in glia, opiate abuse causes widespread metabolic derangement, inflammation, and the disruption of neuron-glial relationships, which likely contribute to neuronal dysfunction, death, and HIV encephalitis. In addition to direct actions on neural cells, opioids modulate inflammation and disrupt normal intercellular interactions among immunocytes (macrophages and lymphocytes), which on balance further promote neuronal dysfunction and death. The neural pathways involved in opiate enhancement of HIV-induced inflammation and cell death, appear to involve MOR activation with downstream effects through PI3-kinase/Akt and/or MAPK signaling, which suggests possible targets for therapeutic intervention in neuroAIDS.
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PMID:Molecular targets of opiate drug abuse in neuroAIDS. 1626 Mar 86

The brain is targeted by human immunodeficiency virus type 1 (HIV-1) during the course of untreated infection, leading to cognitive impairment, neurological damage and HIV encephalitis (HIVE). To study early dynamics of HIV entry into the brain, we examined a unique autopsy series of samples obtained from 15 untreated individuals who died in the presymptomatic stages of infection from non-HIV causes. HIV was detected and quantified by limiting dilution PCR and genetically characterized in the V3 region of env. Limiting dilution was shown to be essential for correct estimation of genetic partitioning between brain- and lymphoid-associated HIV populations. While no actively expressing HIV-infected cells were detected by immunohistochemistry, variable and generally extremely low levels of proviral DNA were detected in presymptomatic brain samples. V3 region sequences were frequently genetically distinct from lymphoid-associated HIV variants, with association index (AI) values similar to those observed in cases of HIVE. Infiltration of CD8 lymphocytes in the brain was strongly associated with expression of activation markers (MHCII; R = 0.619; P < 0.05), the presence of HIV-infected cells (proviral load; R = 0.608; P < 0.05) and genetic segregation of brain variants from populations in lymphoid tissue (AI value, R = -0.528; P approximately 0.05). CD8 lymphocytes may thus limit replication of HIV seeded into the brain in early stages of infection. Neurological complications in AIDS occur when this control breaks down, due to systemic immunosuppression from HIV that destroys CD8 lymphocyte function and/or through the evolution of more aggressive neuropathogenic variants.
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PMID:An immune control model for viral replication in the CNS during presymptomatic HIV infection. 1631 19


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